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Tool works well to pinpoint those who need long-term solutions such as punctal plugs.
An inexpensive tear normalization test (TNT) using carboxymethylcellulose 0.5% drops could be used to help physicians to diagnosis thousands of dry-eye patients.
“[TNT] can detect thousands, if not millions, of undiagnosed dry eyes just with this simple artificial tear drop,” said Robert Latkany, M.D., assistant professor, New York Medical College, and founder of the Center for Ocular Tear Film Disorders, New York.
Dr. Latkany presented the results of his tests at the 2005 ASCRS•ASOA Symposium & Congress during a presentation of his paper, “Functional test to diagnose dry-eye syndrome.” Dr. Latkany won a Best Paper of Session award for his work.
Study data presented by Dr. Latkany showed a drastic improvement in vision when patients used Refresh Plus (Allergan, Irvine, Calif). Vision returned to baseline within a few minutes after the drops were added. If a patient’s vision improved after drops, then dry-eye disease might be present, Dr. Latkany said.
The test also offers dry-eye patients a temporary relief from their irritations — within three to five seconds of application.
“The more severe and the more upset the patient is, and the more findings I see, the larger the improvement of the vision,” he said.
The TNT study
Dr. Latkany measured the best-corrected distance vision in 40 eyes of 20 asymptomatic patients, 40 eyes of 20 dry-eye patients, and 40 eyes of 20 normal patients.
The patients were retested after receiving a carboxymethylcellulose 0.5% drop (Refresh Plus) and completed an Ocular Surface Disease Index questionnaire form.
Other non-viscous artificial tear drops, including Moisture Eyes (Bausch & Lomb, Rochester, N.Y.), MiniDrops (Optics Laboratory Inc. El Monte, Calif.), and TheraTears (sodium carboxymethylcellulose 0.25%, Advanced Vision Research, Woburn, Mass.), provided the same temporary improved visual acuity in dry-eye patients.
Almost all patients in the asymptomatic and symptomatic dry-eye groups had improved best-corrected distance vision after the eye drop was instilled, the study concluded.
In addition, almost all of the normal patients showed no improvement in vision after use of the eye drop.
“I found a nice statistically significant difference; 83% sensitivity rate and 100% specificity rate when looking at greater than one line of acuity improvement,” Dr. Latkany said.
While some of the patients in the normal group did show improvement, Dr. Latkany said that could have been the result of them being misdiagnosed at the study’s onset. It is also possible, he said, for even normal patients to have aberrations.
From the study, Dr. Latkany also said 83% of the symptomatic group showed an improvement of at least two lines of visual acuity, which he called “impressive.”
Test benefits
Dr. Latkany regularly uses the TNT, especially in enhancement cases. If there is an improvement of visual acuity after TNT, he tries to optimize the tear film before he performs enhancement. That method has reduced patient enhancement rates, he said.
Dr. Latkany concluded that there are several benefits from using TNT to detect dry eye.
“It’s available in every eye doctor’s office. It’s simple. It can be performed by a technician or even by the patients themselves,” he said. “It’s captivating. We all had this experience when you put a drop of tears especially after LASIK and patient all say, ‘Wow, what was that?’ They all want to know no more about how to get better.”
Long-term solution?
Dr. Latkany cautioned that TNT is not a long-term solution to dry eye.
“Unless you are going to use the drop every two to three minutes, I’d try to find a more practical approach, such as punctal plugs [various manufacturers],” Dr. Latkany said.
In another study, Dr. Latkany said he looked at 34 eyes on corrected near-eye visual acuity tested before punctal plugs and one month after, and 16 control dry eyes as well. Vision was tested with high-contrast Snellen charts and no drops.
“There was a very statistically significant improvement in the uncorrected near vision and in more severe dry eyes, the greater the improvement of their vision,” Dr. Latkany said. “[In] control dry-eye patients, after one month, some lost a line of vision and some lost a line or two of vision, as can be expected. But the one thing you do see is the very significant improvement of the visual acuity. At least 78% percent gained two lines or more after plug placement.”
Plugs are generally safe, he said, but there is an extrusion rate and there is a foreign-body sensation rate.
“The most important thing I feel is that with the presbyopic dry-eye patients, it’s more than just the loss of accommodation,” he said. “There is an element of aberrations on the ocular surface that contribute to the inability to read, and reducing these aberrations should improve the quality and quantity of their vision.”
Editor’s note: Dr. Latkany has no financial interests related to his comments.
Contact Information
Latkany: 212-832-2020, relief@dryeyedoctor.com |
